As an optical element for diffused light such as scattered light from a scattered light source as object light to be controlled, controlling transmission conditions for the object light so as to selectively pick up, from the object light, a light component with a particular wavelength range and a particular incident angle, and the like, for example, a band-pass filter, which is an interference filter using a dielectric multilayer film, is used (for example, see Patent Documents 1 and 2).